Leptochiton laurae Schwabe & Sellanes, 2010

Sirenko, Boris, 2015, Shallow and deep-sea chitons of the genus Leptochiton Gray, 1847 (Mollusca: Polyplacophora: Lepidopleurida) from Peruvian and Chilean waters, Zootaxa 4033 (2), pp. 151-202 : 161-162

Leptochiton laurae Schwabe & Sellanes, 2010

( Figs 8 A–C, 9–16)

Leptochiton cf. sykesi Sirenko & Gallardo 2005: 89 [non Leptochiton sykesi ( Sowerby III, 1903)] Leptochiton laurae Schwabe & Sellanes 2010: 37 –41, Figs 1 J, 4, 5A–D.

Type. Holotype ( ZSM Mol 20070760).

Type locality. Chile, off Concepcion, 36º22.19’S 73º43.36’W, 846 m.

Material examined. Chile. Near Valdivia, Punta Galera, 39º59’S 73º43’W, 450 m; Canal Concepcion, 50°30’S, 74°55’W (depth unknown); Magellan Strait and Beagle Channel. RV Victor Hensen, st. 1045, EBS, 54°51.8’S, 69°55.6’W, 210 m, 2 spms, 0 4.11.1994, leg. K. Linse; st. 1140, EBS, 54°54.9’S, 68°39.1’W, 310 m, 1 spm, 0 7.11.1994, leg. K. Linse; st. 1270, EBS, 54°55.17’S, 70°45.15’W, 135 m, 1 spm, 21.11.1994, leg. A. Brandt; RV Vidal Garmas, cruise 96, st. 41, AGT, 50°20.9’S, 74°49.3’W, 438 m, 3 spms, 25.10.1996; RV Vidal Garmas, cruise 97, st. 5, AGT, 53°03.6’S, 70°38.2’W, 88 m, 1 spm, 07.10.1997; South Orkney Islands. RV Evrika, cruise 22, dredge 18, 60°24’S, 46°09’W, 1200–1280 m, 1 spm, 0 9.02.1987, leg. I. Smirnov; dredge 32 60°28’S, 47°07.0’W, 285 m, 2 spms, 24.03.1987, leg. I. Smirnov; South Shetland Islands. RV Eltanin, cruise 6, st. 432, Blake trawl, 62°52’S, 59°27’W, 884–935 m, 2 spms, 07.01.1963; RV Polarstern, ANT XVII/3, st. 149, AGT, 62°30.00’S, 56°55.08’W, 911 m, 2 spms, 24.04.2000, leg. B. Sirenko; Kerguelen Islands, RV Skif, cruise 3, st. 170, 49°12.4’S, 68°23.5’E, 145–146 m, 2 spms, 4.1.1971, leg. A. Pushkin; RV Fiolent, cruise 2, st. 82, 47°57’S, 69°02’E, 175 m, 5 spms, 21.10.1972; Crozet Islands. RV Skif., cruise 6, st. 45, 45°42.3’S, 49°35’E, 520–545 m, 4 spms, 6.12.1970, leg. A. Pushkin.

Distribution. Chile from off Concepcion (36°22’S) southwards to the Magellan Strait and Beagle Channel, South Orkney, South Shetland, Kerguelen and Crozet Islands, 88–1200 m.

Remarks. The dorsal scales of this species are variable. The specimens from South Shetland Ids. ( Figs 9–11 ) have dorsal scales without ribs, whereas the specimens from the Beagle Channel ( Figs12–15 ) have scales with or without rib. Moreover small specimens of L. laurae ( Fig.16 ) are very similar to L. medinae . This species resembles Leptochiton sykesi ( Sowerby III, 1903) ( Figures 17–19 ) and L. medinae by longitudinal rows of granules in the central areas of the intermediate valves and features of the radula. L. laurae differs from L. sykesi in the number of aesthete pores (3 in L. laurae and 5 in L. sykesi ), in having dorsal scales which are rarely smooth or have one rib (girdle densely covered by numerous dorsal scales with three ribs in L. sykesi ). Leptochiton laurae differs from L. medinae in the number of aesthete pores (3 in L. laurae and 5 in L. medinae ), and L. medinae has dorsal scales with 6 ribs. Additionally the valves are subcarinated in L. laurae vs. rounded in L. medinae , quincuncially arranged granules in the lateral areas vs. radiating rows of granules and smooth marginal scales vs. ribbed marginal scales in L. medinae .

Figures

FIGURE 1. Leptochiton kerguelensis Haddon, 1864, (ZISP 2257). Beagle Channel, RV Victor Hensen, st. 1213. BL— 4.0 mm. A. Complete specimen, dorsal view; B. Complete specimen, lateral view; C. Valve I, dorsal view; D. Valve V, dorsal view; E. Valve VIII, dorsal view; F. Valve IV, ventral view; G. Valve VIII, lateral view; H. Valve V, rostral view.

FIGURE 8. Preserved specimens of three species. A. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2259). Chile, near Valdivia, BL— 16.0 mm, dorsal and lateral views; B. L. laurae, (ZISP 2260). South Orkney Ids, RV Evrika, dredge 32, BL— 13.0 mm, dorsal and lateral views; C. L. laurae, (ZISP 2261). South Shetland Ids., RV Polarstern, st. 149, BL— 10 mm, dorsal and lateral views; D. Leptochiton longibranchiae n. sp., paratype, (ZISP 2213) BL— 9.0 mm, ventral view; E. Leptochiton peruvianus n. sp., paratype, (ZISP 2211), BL— 6.5 mm, dorsal and lateral views. Scale bars 1.0 mm.

FIGURE 9. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2262). South Shetland Ids., RV Polarstern, st. 145, BL— 10.0 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve V, detail of tegmentum surface of central area; E. Valve VIII, lateral view.

FIGURE 10. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2262). South Shetland Ids., RV Polarstern, st. 145, BL— 10.0 mm. A. Dorsal, marginal and ventral scales and needles; B. Central portion of radula.

FIGURE 11. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2262). South Shetland Ids., RV Polarstern, st. 145, BL— 10.0 mm. A. Sutural needle; B, C. Dorsal scales; D. Marginal needle; E, F. Ventral scales; G. Head of major lateral tooth; H. Valve V, rostral view; I. Valve VIII, lateral view; J. Aesthete group in central area. Scale bar 100 µm (A – G) and 1.0 mm (H, I).

FIGURE 12. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2263). Beagle Channel, RV Victor Hensen, st. 1270, BL— 12 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve IV, ventral view; E. Valve V, detail of tegmentum surface of central area; F. Valve VIII, lateral view; G. Valve V, rostral view.

FIGURE 13. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2264). Beagle Channel, RV Victor Hensen, st. 1045, BL— 11.0 mm. A. Dorsal, marginal and ventral scales and needles; B. Central portion of radula.

FIGURE 14. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2264). Beagle Channel, RV Victor Hensen, st. 1045, BL— 11.0 mm. A. Sutural needle; B, C. Dorsal scales; D. Dorsal needle; E, F. Marginal needles; G, H. Ventral scales; I. Central and first lateral teeth of radula; J, K. Heads of major lateral tooth; L. Valve V, rostral view; M. Valve VIII, lateral view; N. Aesthete group in central area. Scale bar 100 µm (A – K) and 1.0 mm (L, M).

FIGURE 15. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2264). Beagle Channel, RV Victor Hensen, st. 1045, BL— 11.0 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve IV, ventral view; E. Valve V, detail of tegmentum surface of central area; F. Valve VIII, lateral view; G. Central portion of radula.

FIGURE 16. Leptochiton laurae Schwabe & Sellanes, 2010, (ZISP 2265). Beagle Channel, RV Victor Hensen, st. 1140, BL— 3.0 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Dorsal, marginal and ventral scales and needles; E. Central portion of radula.

FIGURE 17. Leptochiton sykesi (Sowerby III, 1905), (ZISP 2266). South Africa, near Cape Town, one specimen deposited in ZISP, BL— 18.0 mm. A. Valve I, dorsal view; B. Valve V, dorsal view; C. Valve VIII, dorsal view; D. Valve VIII, detail of tegmentum surface of antemucronal area; E. Valve V, detail of tegmentum surface of central area; F. Valve VIII, lateral view; G. Valve V, rostral view.

FIGURE 18. Leptochiton sykesi (Sowerby III, 1905), (ZISP 2266). South Africa, near Cape Town, one specimen deposited in ZISP, BL— 18.0 mm. A. Dorsal, marginal and ventral scales and needles; B, D. Central portion of radula; C. Dorsal scales and needles.

FIGURE 19. Leptochiton sykesi (Sowerby III, 1905), (ZISP 2266). South Africa, near Cape Town, one specimen deposited in ZISP, BL— 18.0 mm. A. Sutural needle; B, C. Dorsal scales; D. Dorsal needle; E. Marginal needle; F. Ventral scales; G. Central and first lateral teeth; H. Head of major lateral tooth; I. Aesthete group in central area. Scale bar 100 µm (A – H).